cleanup useless return sentence

[mirror_qemu.git] / slirp / ip.h

/*
 * Copyright (c) 1982, 1986, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)ip.h	8.1 (Berkeley) 6/10/93
 * ip.h,v 1.3 1994/08/21 05:27:30 paul Exp
 */

#ifndef _IP_H_
#define _IP_H_

#ifdef HOST_WORDS_BIGENDIAN
# undef NTOHL
# undef NTOHS
# undef HTONL
# undef HTONS
# define NTOHL(d)
# define NTOHS(d)
# define HTONL(d)
# define HTONS(d)
#else
# ifndef NTOHL
#  define NTOHL(d) ((d) = ntohl((d)))
# endif
# ifndef NTOHS
#  define NTOHS(d) ((d) = ntohs((uint16_t)(d)))
# endif
# ifndef HTONL
#  define HTONL(d) ((d) = htonl((d)))
# endif
# ifndef HTONS
#  define HTONS(d) ((d) = htons((uint16_t)(d)))
# endif
#endif

typedef uint32_t n_long;                 /* long as received from the net */

/*
 * Definitions for internet protocol version 4.
 * Per RFC 791, September 1981.
 */
#define	IPVERSION	4

/*
 * Structure of an internet header, naked of options.
 */
struct ip {
#ifdef HOST_WORDS_BIGENDIAN
	uint8_t ip_v:4,			/* version */
		ip_hl:4;		/* header length */
#else
	uint8_t ip_hl:4,		/* header length */
		ip_v:4;			/* version */
#endif
	uint8_t		ip_tos;			/* type of service */
	uint16_t	ip_len;			/* total length */
	uint16_t	ip_id;			/* identification */
	uint16_t	ip_off;			/* fragment offset field */
#define	IP_DF 0x4000			/* don't fragment flag */
#define	IP_MF 0x2000			/* more fragments flag */
#define	IP_OFFMASK 0x1fff		/* mask for fragmenting bits */
	uint8_t ip_ttl;			/* time to live */
	uint8_t ip_p;			/* protocol */
	uint16_t	ip_sum;			/* checksum */
	struct	in_addr ip_src,ip_dst;	/* source and dest address */
} QEMU_PACKED;

#define	IP_MAXPACKET	65535		/* maximum packet size */

/*
 * Definitions for IP type of service (ip_tos)
 */
#define	IPTOS_LOWDELAY		0x10
#define	IPTOS_THROUGHPUT	0x08
#define	IPTOS_RELIABILITY	0x04

/*
 * Definitions for options.
 */
#define	IPOPT_COPIED(o)		((o)&0x80)
#define	IPOPT_CLASS(o)		((o)&0x60)
#define	IPOPT_NUMBER(o)		((o)&0x1f)

#define	IPOPT_CONTROL		0x00
#define	IPOPT_RESERVED1		0x20
#define	IPOPT_DEBMEAS		0x40
#define	IPOPT_RESERVED2		0x60

#define	IPOPT_EOL		0		/* end of option list */
#define	IPOPT_NOP		1		/* no operation */

#define	IPOPT_RR		7		/* record packet route */
#define	IPOPT_TS		68		/* timestamp */
#define	IPOPT_SECURITY		130		/* provide s,c,h,tcc */
#define	IPOPT_LSRR		131		/* loose source route */
#define	IPOPT_SATID		136		/* satnet id */
#define	IPOPT_SSRR		137		/* strict source route */

/*
 * Offsets to fields in options other than EOL and NOP.
 */
#define	IPOPT_OPTVAL		0		/* option ID */
#define	IPOPT_OLEN		1		/* option length */
#define IPOPT_OFFSET		2		/* offset within option */
#define	IPOPT_MINOFF		4		/* min value of above */

/*
 * Time stamp option structure.
 */
struct	ip_timestamp {
	uint8_t	ipt_code;		/* IPOPT_TS */
	uint8_t	ipt_len;		/* size of structure (variable) */
	uint8_t	ipt_ptr;		/* index of current entry */
#ifdef HOST_WORDS_BIGENDIAN
	uint8_t	ipt_oflw:4,		/* overflow counter */
		ipt_flg:4;		/* flags, see below */
#else
	uint8_t	ipt_flg:4,		/* flags, see below */
		ipt_oflw:4;		/* overflow counter */
#endif
	union ipt_timestamp {
		n_long	ipt_time[1];
		struct	ipt_ta {
			struct in_addr ipt_addr;
			n_long ipt_time;
		} ipt_ta[1];
	} ipt_timestamp;
} QEMU_PACKED;

/* flag bits for ipt_flg */
#define	IPOPT_TS_TSONLY		0		/* timestamps only */
#define	IPOPT_TS_TSANDADDR	1		/* timestamps and addresses */
#define	IPOPT_TS_PRESPEC	3		/* specified modules only */

/* bits for security (not byte swapped) */
#define	IPOPT_SECUR_UNCLASS	0x0000
#define	IPOPT_SECUR_CONFID	0xf135
#define	IPOPT_SECUR_EFTO	0x789a
#define	IPOPT_SECUR_MMMM	0xbc4d
#define	IPOPT_SECUR_RESTR	0xaf13
#define	IPOPT_SECUR_SECRET	0xd788
#define	IPOPT_SECUR_TOPSECRET	0x6bc5

/*
 * Internet implementation parameters.
 */
#define	MAXTTL		255		/* maximum time to live (seconds) */
#define	IPDEFTTL	64		/* default ttl, from RFC 1340 */
#define	IPFRAGTTL	60		/* time to live for frags, slowhz */
#define	IPTTLDEC	1		/* subtracted when forwarding */

#define	IP_MSS		576		/* default maximum segment size */

#if SIZEOF_CHAR_P == 4
struct mbuf_ptr {
	struct mbuf *mptr;
	uint32_t dummy;
} QEMU_PACKED;
#else
struct mbuf_ptr {
	struct mbuf *mptr;
} QEMU_PACKED;
#endif
struct qlink {
	void *next, *prev;
};

/*
 * Overlay for ip header used by other protocols (tcp, udp).
 */
struct ipovly {
	struct mbuf_ptr ih_mbuf;	/* backpointer to mbuf */
	uint8_t	ih_x1;			/* (unused) */
	uint8_t	ih_pr;			/* protocol */
	uint16_t	ih_len;			/* protocol length */
	struct	in_addr ih_src;		/* source internet address */
	struct	in_addr ih_dst;		/* destination internet address */
} QEMU_PACKED;

/*
 * Ip reassembly queue structure.  Each fragment
 * being reassembled is attached to one of these structures.
 * They are timed out after ipq_ttl drops to 0, and may also
 * be reclaimed if memory becomes tight.
 * size 28 bytes
 */
struct ipq {
        struct qlink frag_link;			/* to ip headers of fragments */
	struct qlink ip_link;				/* to other reass headers */
	uint8_t	ipq_ttl;		/* time for reass q to live */
	uint8_t	ipq_p;			/* protocol of this fragment */
	uint16_t	ipq_id;			/* sequence id for reassembly */
	struct	in_addr ipq_src,ipq_dst;
} QEMU_PACKED;

/*
 * Ip header, when holding a fragment.
 *
 * Note: ipf_link must be at same offset as frag_link above
 */
struct	ipasfrag {
	struct qlink ipf_link;
	struct ip ipf_ip;
} QEMU_PACKED;

#define ipf_off      ipf_ip.ip_off
#define ipf_tos      ipf_ip.ip_tos
#define ipf_len      ipf_ip.ip_len
#define ipf_next     ipf_link.next
#define ipf_prev     ipf_link.prev

/*
 * Structure stored in mbuf in inpcb.ip_options
 * and passed to ip_output when ip options are in use.
 * The actual length of the options (including ipopt_dst)
 * is in m_len.
 */
#define MAX_IPOPTLEN	40

struct ipoption {
	struct	in_addr ipopt_dst;	/* first-hop dst if source routed */
	int8_t	ipopt_list[MAX_IPOPTLEN];	/* options proper */
} QEMU_PACKED;

#endif